How to Replace a Radiator Hose on a 2018 GMC Sierra 1500
Step-by-step instructions with tools, parts, coolant refill, leak checks, and safety tips
How to Replace a Radiator Hose on a 2018 GMC Sierra 1500
Step-by-step instructions with tools, parts, coolant refill, leak checks, and safety tips
Assumption: This guide covers replacing a main radiator hose on your Sierra, with notes for upper or lower hose where the procedure differs.
🔧 Radiator Hose - Replacement
The radiator hose carries coolant between the engine and radiator. A cracked, swollen, or leaking hose can cause overheating fast, so replacement is important as soon as you see seepage or softness.
Difficulty Level: Beginner | Estimated Time: 1-2 hours
⚠️ Safety & Precautions
- Let the engine go completely cold before opening the cooling system.
- Hot coolant can spray out under pressure and cause serious burns.
- Use only the correct Dex-Cool coolant mixture for this Sierra.
- Keep the coolant reservoir cap loose only after the engine is cold.
- Battery disconnect is not required for this repair.
🔧 Required Tools
You'll need the following tools for this repair:
- Drain pan
- Flat blade screwdriver
- Hose clamp pliers
- 10mm socket
- Ratchet
- Extension
- Pliers
- Funnel
- Safety glasses
- Gloves
- Jack stands
- Floor jack (rated 3-ton minimum)
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Radiator hose - Qty: 1
- Radiator hose clamps - Qty: 2
- Dex-Cool coolant - Qty: 1-2 gallons
- Distilled water - Qty: 1-2 gallons
- Replacement hose spring clip or retaining clip - Qty: 1, if equipped
📋 Before You Begin
- Park on level ground and set the parking brake.
- Let the engine cool fully.
- Raise the front of the truck only if you need more room under it.
- Place a drain pan under the radiator before opening any hose connection.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Remove pressure from the cooling system
- With the engine cold, slowly loosen the coolant reservoir cap to release any leftover pressure.
- If the cap is stuck, stop and let the system sit longer.
Step 2: Drain coolant below the hose level
- Use a drain pan under the radiator.
- If equipped with a radiator drain, open it carefully.
- If not, remove the lower hose first and let coolant drain into the pan.
- Catch as much coolant as possible for reuse if it is clean.
Step 3: Remove the old hose clamps
- Use hose clamp pliers or a flat blade screwdriver, depending on clamp style.
- Slide spring clamps back on the hose.
- If yours uses screw clamps, loosen them with a screwdriver or 8mm nut driver if needed.
Step 4: Remove the old radiator hose
- Use pliers to gently twist the hose loose at each end.
- Pull the hose off the radiator neck and engine fitting.
- If it is stuck, carefully work it free with a flat blade screwdriver under the hose edge.
- Do not damage the plastic radiator neck or metal tube.
Step 5: Compare and install the new hose
- Compare the new hose to the old one for length and bend shape.
- Transfer any clips or sleeves from the old hose if the new one does not include them.
- Install new clamps onto the hose before pushing it on.
- Push the hose fully onto both fittings until it seats against the stop.
Step 6: Position and secure the clamps
- Use hose clamp pliers to place the clamps over the hose nipples.
- Position them behind the raised bead on each fitting.
- Make sure the clamp sits flat and even.
- Torque to 3-5 Nm (27-44 in-lbs) if using worm-gear style clamps.
Step 7: Refill the cooling system
- Use a funnel to fill the reservoir with the correct Dex-Cool coolant mix.
- Top off to the proper mark.
- Check for spills around the hose ends.
Step 8: Bleed air from the system
- Start the engine with the cap off if the reservoir design allows it.
- Set the heater to hot and the blower on low.
- Let the engine reach operating temperature.
- Watch for bubbles in the reservoir and add coolant as the level drops.
- Install the cap once the level stabilizes.
- Air pockets can cause overheating.
Step 9: Inspect for leaks
- Use a flashlight to check both hose ends and clamp areas.
- Look for seepage after the engine reaches temperature.
- Shut the engine off and recheck after a short cool-down.
✅ After Repair
- Drive the Sierra for a short test route.
- Watch the temperature gauge closely.
- Recheck coolant level after the engine cools again.
- Inspect the hose and clamps for fresh leaks over the next few trips.
💰 DIY vs Shop Cost
Shop Cost: $180-$380 (parts + labor)
DIY Cost: $35-$110 (parts only)
You Save: $145-$270 by doing it yourself!
Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1-2 hours.
🎯 Ready to get started?
HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.


















